Lithium 3-thia-7, 7, dimethyl-7-trimethylsiloxy-7-silaheptanoate



Patented Jan. 22, 1952 LITHIUM 3-THIA-7,7,D1IMETHYL-7-TRI- METHYLSILOXY-7 -SILAHEPTANOATE Charles A. Burkhard, Alplaus, N. Y., assignor to General Electric Company, a corporation of New York No Drawing. Application August 18, 1949, Serial No. 111,094

1 Claim. 1

The present invention relates to alkali salts of organosilicon compounds. It is particularly concerned with water soluble compounds useful as detergents and emulsifying agents and having the general formula wherein n is from to 10, preferably 0 to 1, m is an integer of from 2 to 3 and M is an alkali metal, particularly lithium, sodium or potassium.

Representative acids employed in the manufacture of the detergents include the following:

1. 3-thia-6-sila-6,6-dimethylheptanoic acid (CH3) aSiCH2CI-I2SCH2CO2H 2. 3-thia-7-sila-7,7-dimethy1octanoic acid (CHa) 3SICH2CH2CH2SCH2CO2H 3. 3 thia 7,7 dimethyl 7 trimethylsiloxy- 7-silaheptanoic acid (CH3) aSiOSi (CH3)2 (CH2) 3SCH2CO2H These acids and their preparation by the reaction of thioglycolic acid and a suitable alkenyl silane or siloxane of the formula wherein R is a vinyl or allyl group are specifically described and claimed in my copending application SerialNo. 111,091 filed concurrently herewith and assigned to the same assignee as the present invention.

In accordance with the present invention, an acid of the above type is neutralized with a solution of an alkali metal base and the alkali metal salt recovered by evaporation of the solvent. The product appears to have substantially the same detergent properties as ordinary organic acid soaps of the same or substantially the same molecular weight. Due to the presence of the sulfur atom, the soaps of the present invention may also be used in ore floatation processes such as are employed in the recovery of lead, copper, silver, gold and other heavy metals. They may also be employed as lubricant additives in lubricating oils.

In order that those skilled in the art better may understand how the present invention may be carried into effect, the following illustrative examples are given:

Example 1.A solution of 3-thia-7-trimethylsiloxy-7,7-dimethyl-7-silaheptanoic acid in 95 percent ethyl alcohol was neutralized by the addition of an equivalent quantity of 0.5 N sodium hydroxide. The water and alcohol solvents were removed by heating on a steam bath followed by heating to dryness in a vacuum oven at 75 C.

Analysis of the product for sulfur gave 9.99 and 10.08%; calculated 10.60.

Aqueous solutions of the resultant soap exhibited good detergent properties in tests including the washing of soiled white cloth and the removal of dirt from ones hands. Considerable stable foam was obtained upon shaking of the aqueous solutions. A similar soap was obtained by substituting KOI-I for the NaOH.

Example 2.A quantity of 3-thia-7-trimethylsiloxy-7 ,7 -dimethyl-7-silaheptanoic acid was neutralized by the addition of a solution of lithium hydroxide and the resultant lithium soap recovered by evaporating the solvent. This soap differs from the lithium soap prepared from stearic acid in that it is soluble in acetone. It formed a large quantity of foam in distilled Water and was precipitated from aqueous solutions thereof by ions such as calcium and magnesium.

Example 3.-3-thia-6,6-dimethylheptanoic acid and 3-thia-7-sila-7,7-dimethyloctanoic acid were respectively neutralized by the addition of 0.5 N sodium hydroxide solution. The products were aqueous solutions of the sodium salts of the acids having foaming and detergent properties similar to the soaps of the previous examples.

While the invention has been particularly described with reference to the use of the designated acids, it will be obvious the hydrolyzable esters thereof can be substituted therefor.

The compounds herein described have also been employed as emulsifying agents for preparing aqueous emulsions of liquid organopolysiloxanes, such as, methyl polysiloxane oils.

What I claim as new and desire to secure by Letters Patent of the United States is:

Lithium 3-thia-7,7-dimethyl-7-trimethylsiloxy- 7-silaheptanoate.

CHARLES A. BURKHARD.

REFERENCES CITED The following references are of record in tne file of this patent:

UNITED STATES PATENTS Name Date Burke July 18, 1950 OTHER REFERENCES Number (1945), page 356, Interscience, publisher, New

York.

Swartz et al.: "Surface Acting Agents" (1949), page 41, Interscience, publisher, New York. 

